Bumper jack



L. D. NILSON Feb. 7, 1939.

BUMPER JACK Filed March 23, 1937 Patented Feb. 7,1939

UNITED STATES PATENT OFFICE Vulcan Manufacturing Co.,

Inc., St. Paul,

Minn., a corporation oi' Minnesota Application March k23,

7 Claims.v

An object of my invention is to provide a bumper jack of simple, durable and inexpensive construction.

A further object is to provide a jack structure of post-like construction having an operating member extending froml the upper end thereof and reciprocable vertically, lifting means being provided within the post-like structure which is vertically slidable relative thereto and has a liftl" ing sleeve telescopically movable on the exterior oi the post-like structure, a hook clamp being adjustable on this lifting sleeve and being adaptable for engaging the bumper of an automobile for lifting the bumper and thereby one end of J the automobile.

Still a further object is to provide 'a bumper `lack structure which has improved details of construction over the bumper jack disclosed in my Patent No. 2,064,445dated December 15, 1936,

2 particularly with respect to improved mechanical details.

A further object is to provide in my improved jack a lifting sleeve lwhich soY telescopes with `a vertical cylinder that in all positions of extension the jack structure is extremely rigid.

Still a further object is to provide a steady sleeve for the piston rod which enclcses the upper portion of the jack and telescopes over the ex terior thereof to prevent any undesired bending o or binding of the Apiston rod of the pump within the jack.

Still a further object is to provide a novel intake and outlet valve arrangement including an intake valve which is readily operable in one position of the pump of the jack to release the oil pressure within the jack, screw threaded means being provided for association and operation after the pressure has been released, the operation of the screw threaded means opening the outlet valve to permit the jack to lower.

Still a further object is to provide means for sealing the jack against undesired leakage of oil therefrom when the jack is to be placed in the tool box.

Another object is to provide an automatic release means in the jack to prevent over extension thereof and consequent `damage to the jack by bending of the tubular telescoping parts thereof.

With these and other objects in View, my invention consists in the construction, arrangement and combination of the various parts of the device, whereby the objects 'contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawing, in which:

1937, serial No1-1324565 l (ci. ass- 93) Figure 1 is a side elevation of a ybumper jack structure embodying my invention and showing it cooperating with a bumper bar.

Figure 2 is an enlarged sectional view on the line 2-2 of Figure l showing the lifting means adjacent lowered position, portions of the struc- 'ture being broken away to conserve space on the I drawing, and such portions being indicated at a and b in Figure 2 which correspond to the portions within the brackets 2a and 2b of Figure l.

Figure 3 is a similar sectional view-showingv the parts in a different position.

Figure 4 is a`sectional View on the line 4--4of Figure 2 showing a plan view of the intake valve. .15.

for my jack structure. It 'is provided with a plurality of 'prongs I2 surrounding a`ball seat I4. A ball I6, whichforms the lower head of a lift cylin- 'der i8, is seated in the seat' M. During assem bly, after the ball is so seated, the 'prongs I2 are bent inwardlyv as clearly shown in Figures 1 and 5 toretain the ball against displacement from the seat thereafter. l

The prongs i2 are spaced so that notchesA are, provided between them which permit the foot I0 to be swung to the dotted position shown in Figure 2, when it is desirable to place the jack in the tool box. y y

The lifting cylinder i8 has telescopically moun-tl ed thereon a lifting sleeve 20. A packing nut 22 is provided at the lower end of the lifting sleeve 20 to prevent escape of oil. Within"the lifting cylinder I8 I- provide a cup leather lifting piston 24 connected with a tubular lifting piston rod 26. The upper end of the rod 26 is connected by a head 28 to the upper end of the lifting sleeve 20, whereby the two are simultaneously movable with the lifting piston 24 relative to the lifting I cylinder IB. A clamp hook 30 is vertically slidable on the lifting sleeve 20, this being 'a split band of the ordinary type having a clamp bolt 32 for positively positioning it relative to the ,sleeve 20. It is provided with a hook 34 adapted to engage a bumper bar or bumper supporting bar 36 of an automobile as shown in Figure 1. The lifting cylinder at its lower end has a removable plug I9 for permitting introduction of oil from an oil can if any is lost by leakage.

For raising the piston 24 and thereby the clamp hook 30, I provide a pump structure which will now be described. l

A fitting 38 extends upwardly from the cup leather piston 24 and terminates in a head 40 which connects to the lower end of the lifting piston rod 26. The spaces betneen the cylinder I8 and the sleeve 20, within the cylinder I8 and Within the tubular lifting piston rod 26, constitute a reservoir for oil. The oil has been omitted from the drawing to avoid confusion of details.

Ports 42 and 44 serve to communicate the reservoir spaces with each other. The lower end of the member 40 constitutes an intake valve seat indicated at 46. An intake valve 46 having a disk-like upper surface is provided, which surface normally is seated against the seat 46 by a spring 62. The intake valve 48 has a pair of these disks which, as shown in Figure 4, are of hexagonal shape so oil can readily pass their peripheries. An outlet valve 64 of the ordinary ball type is provided within the lower end of the fitting 38. It is normally seated by a spring 66. Extending upwardly from the head 40 and arranged within the lifting piston rod 26 is a pump cylinder 68. A pump plunger 60 is reciprocable therein.

The intake valve 46 of Figure 2 may be modified as in Figure 6, showing a single disk 60 on the valve 48 and a guide sleeve 6| telescoping over a pump plunger 60. 'I'he plunger 60 has a stem 6| to engage the ball valve 64 instead oi a stem 48 for this purpose, as shown in Figure 3.

Returning to Figure 2, the upper end of the plunger 60 extends through a packing 62 in the head 28 and terminates in a head 64 relative to which it is screw threadedly mounted for adjusting purposes.

A countersunk lock nut for the plunger 60 is indicated at 66. In Figure 2 the plunger 60 is shown in its lowered position. During operation it extends some distance out of the packing 62 and to reinforce it against bending, I provide a steady sleeve 68 connected with the head 64 and telescoping over the lifting sleeve 26.

From the construction of the parts just described, it will be obvious that upon reciprocation, the plunger 66 will, upon upward movement when the intake valve 48 is seated. produce a vacuum between the seat 46 and the outlet valve 64. This pulls the intake valve 48 oi its seat so that oil will be'drawn downwardly through ports 18 in the head 40, and then upwardly into the pump cylinder 66. On the down stroke the valve 48 will first be closed, and thereafter the oil will be forced through the outlet valve 64 into the lifting cylinder I6 below the lifting piston 24, thus forcing it upwardly. Continued reciprocation of the plunger 60 will cause the jack to .raise its supporting hook 84 until the piston 24 passes the port 44, whereupon upward movement of the jack is limited because any oil pumped to the lifting cylinder thereafter will by-pass back to the reservoir space between the cylinder I8 and the sleeve 20. 'I'his prevents excessive extension of the jack. Due to the disk-like character of the valve 48 and to its large size, but slight vacuum is needed to unseat it on the up stroke of the plunger 60 when the oil is thick during cold weather.

When it is desired to lower the jack the plunger 60 is moved to its downward limit of movement shown in Figure 2, which opens the intake valve 48, thus relieving the pressure on the oil caused by the piston 24 supporting the weight of the automobile. Thereafter the outlet valve 54 may be opened for permitting the oil below the piston 24 to flow back into the reservoir spaces as a result of the weight of the automobile forcing the piston 24 downwardly. Opening the valve 64 is accomplished by a screw threaded connection indicated at 12 which assumes coacting relationship only upon clockwise rotation of the head 64 after the position of Figure 2 is reached.

Figure 3 illustrates the parts having been rotated for pushing the outlet valve 64 off its seat to permit lowering of the jack. By the use of the screw threaded connection a very fine adjustment of the valve 64 can be secured for either slow or fast lowering of the jack as desired.

After the jack has been used, the head 64 can be further rotated so that a gasket Washer 14 therein will engage the upper end of the head fitting 28 to provide an additional insurance against leakage of oil from the jack around the ,pump plunger 68.

During pumping operations excessive outward movement of the plunger 60 is prevented by a collar 6 I thereon, the inner end of the head 28 acting as a stop therefor.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

l. In a hydraulic jack structure, a cylinder, a lifting member slidable longitudinally relative thereto, lifting means within said cylinder and having an operating handle projecting therefrom, said operating handle being reciprocable for lifting operations, said lifting means including a pump cylinder, a disk-like intake valve, an outlet valve and a pump plunger, said pump plunger being operatively connected with said operating handle, said intake valve being engaged and opened by said pump plunger at one limit of its reciprocating movement and a screw threaded connection between said operating handle and said lifting member, associable and operable after such limit of movement has been reached, to open said outlet valve.

2. For a. hydraulic jack having a lifting member and lifting means having an operating handle projecting from said lifting member, said operating handle being reciprocable for lifting operations and said lifting means including a pump cylinder, intake and outlet valves and a pump plunger and said pump plunger being operatively connected with said operating handle; said intake f valve being engaged and opened by said pump plunger at one limit of its reciprocating movement and having an extension, and a rotatable screw-threaded connection between said operating handle and said lifting member, associable and operable after such limit of movement has been reached, to cause said extension to open said outlet valve.

3. In a jack of the character described, a vertical cylinder, a lifting sleeve slidable longitudinally relative thereto, lifting means comprising a lifting piston operatively connected with said lifting sleeve a pump to raise said lifting sleeve and including intake and outlet valves an operating and release rodfor said pump extending from the upper end of said lifting sleeve and a screw-threaded connection between said rod and said lifting sleeve, associable after the rod has been reciprocated to its lowermost position and A thereby opened said intake valve and thereafter operable to eifect release action by opening said outlet valve upon rotation of the screw threaded connection.

4. For a Jack of the character describeclhaving a lifting sleeve slidable longitudinally relative thereto and lifting means for said lifting sleeve and comprising a lifting piston, a pump for pumping oil and an operating memberfor said pump, said pump including intake and outlet valves and a pump plunger; said pump plunger being operable to engage and open the intake valve at the lower limit oi reciprocation of the pump plunger and to thereafter cause the intake valve to engage and open the outlet valve upon rotation of the pump plunger. v

5. In a jack of the character described, a vertical support, a lifting sleeve slidable telescopically thereon, lifting mechanism contained within said sleeve and operatively connected thereto and an actuating sleeve for said lifting mechanism operatively connected thereto and slidable telescopically of said lifting sleeve.

6. In a jack of the character described, a vertical support, a lifting sleeve slidable telescopically thereon, lifting mechanism contained Within saidsleeve and operatively connected thereto and an actuating sleeve for said lifting mechanism operatively connected thereto and slidable telescopically of said lifting sleeve whereby sliding movement of the actuating sleeve functions to operate the lifting mechanism for raising the lifting sleeve.

7. In a jack ofthe character described, a vertical support, a lifting sleeve slidable telescopically relative thereto, lifting mechanism for operating said lifting sleeve, said lifting mechanism being operatively connected with said lifting sleeve and an actuating sleeve for said lifting mechanism operatively connected thereto and slidable telescopically of said lifting sleeve whereby sliding movement of the. actuating sleeve functions to operate the lifting mechanism for elevating the lifting sleeve relative to the vertical support.

LEONARD D. NLsoN. 

